The prize for the most important book with the most misleading title might go to "The End of Liberalism,' published in 1969 by Theodore J. Lowi, who died less than three months ago. In the second edition of that book, the Cornell political scientist sets forth in 11 enigmatic words why he once was named by his peers as the most influential political scientist in the country:

"The most fundamental political problem of our time is our politics.'

That sentence was written in the Jimmy Carter years, a reminder to liberals that their remarks about recent failed presidencies ought not to include only Richard Nixon, who is enjoying a mini rehabilitation, and George W. Bush, whose rehabilitation may be a decade or so off.

One of the tenets of Lowi's book is that the two parties are the captives of their respective interest groups: "Congressmen are guided in their votes, presidents in their programs, and administrators in their discretion by whatever organized interests they have taken for themselves as the most legitimate; and that is the measure of the legitimacy of demands and the only necessary guidelines for the framing of the laws.'

That notion may still be true in certain corners of the Capitol, but may no longer be true in the White House, for whose call exactly - besides perhaps the wealthy, who, as the Bill Clinton years showed us, includes many Democratic masters of the universe - does Donald J. Trump respond to?

Not, except marginally, to the austerity tradition of the Republican Party of Robert Taft and Robert Dole; Trump is girding to spend billions on an infrastructure initiative that Democrats will embrace and that Republicans will accede to in the hopes that their districts will get newly paved roads and reinforced bridges. But when, early last week, he broached the notion that he might entertain raising the gasoline tax to pay for this spending, he made it clear he wasn't a doctrinaire tax-cutter in the Ronald Reagan and Jack Kemp tradition.

Not, except rhetorically, to the blue-collar constituency that helped make him the 45th president; his tax plan, fortified by reductions in corporate levies and the elimination of the Alternative Minimum Tax and inheritance taxes, is not aimed at them.

Trump would be the first to say he is a force without precedent in American politics, and it isn't only his innovative interpretation of the origins of the Civil War that suggests he is right.

There is no worship of the past in Trump, who in fact broke all historical barriers by embracing Andrew Jackson, arguably a populist like Trump but ordinarily regarded as the midwife of the modern Democratic Party.

If Lowi was right that the most fundamental political problem of our time is our politics, did Trump cause that problem, or did he reflect it? Did the Freedom Caucus of the contemporary Republican Party cause it, or did it reflect it? Is the increasingly leftist Democratic Party a cause or a reflection of that crisis?

The short answer to all three: Yes.

In a few decades, historians will have a longer answer, just as they did in the decades after the Civil War.

But right now we can only try to see through a glass, darkly. And what we see is that nothing is quite as it appears - and nothing is as it was in the past.

Look, for example, at the spending compromise that emerged from Capitol Hill last week, shaped as much by the urgency of preventing a government shutdown as by any coherent ideological test. It doesn't have many of the Republican priorities and is so loaded with notions repugnant to them that House Minority Leader Nancy Pelosi of California was able to issue a press release bragging that the bill 'reflects Democrats' values to protect health care, environment and education.'

Which party did you say controls Congress today?

The Republicans, who campaigned to repeal the Affordable Care Act and whose president is determined to build a wall at the Mexican border, aren't close to being in charge of the so-called Republican Congress. But more than that, the new Republicans are conducting themselves as no rump group has behaved before.

At the same time, Trump may not really be the populist that commentators sometimes say he is.

"Like anything - liberalism, fascism - these kinds of definitions are broad,' said Sheri Berman, a Barnard College political scientist specializing in American populism. "There is a difference between Trump's rhetoric, which is classic populism, and his policies. He's governed in a fairly traditional way.'

So in all this confusion, two things are clear. The first is that we no longer have the language to describe our politics. The second is that the most fundamental political problem is our politics.

David Shribman, a Pulitzer Prize winner in journalism, is executive editor of the Pittsburgh Post-Gazette.